System and method for secure real-time cloud services

ABSTRACT

A system and method for providing secure, end-to-end data service enabling real-time data over the Internet is disclosed. The system and method provides a communication framework between sensors, devices, and machinery and the users of that data from any remote location that is connected to the Internet without requiring open inbound firewall ports, while at the same time enabling high data rates, low latency and full bi-directionality. The graphical and networking features of RIA frameworks in combination with the disclosed system and method provide low-latency, real-time data applications in a web browser securely over the Internet.

CROSS-REFERENCE TO RELATED APPLICATION

This present application is a continuation of U.S. application Ser. No.14/542,427, filed Nov. 14, 2014, now U.S. Pat. No. ______, which claimspriority to U.S. Provisional Application No. 62/023,172, filed Jul. 10,2014, and U.S. Provisional Application No. 62/035,473, filed Aug. 10,2014, the contents of which are incorporated herein by reference.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

BACKGROUND OF THE INVENTION

Real-time data refers to any digital or analog information that shouldbe processed and/or transmitted within a certain amount of time afterthat data is originally created. The time elapsed from the moment thatthe data is created until it is processed and/or transmitted is known aslatency. The maximum latency allowable for any particular real-timeapplication is application-dependent. Applications where the maximumlatency is a strict requirement can be referred to as “hard” real-timeapplications, while applications where the maximum latency is not astrict requirement can be referred to as “soft” real-time applications.Soft real-time applications need only satisfy an application-dependent,often subjective, measure of “fast enough”. Non-real-time data is datathat is not required to satisfy any particular latency requirement.

The term “data” may refer to hard real-time, soft real-time ornon-real-time data. “Real-time data” may refer to hard real-time or softreal-time data.

Real-time data is typically generated due to a physical process or acomputer program external to the computer system that processed thedata. For example, real-time data may include: information from anindustrial process control system such as motor status, fluid tanklevel, valve position, conveyor speed and so on; prices, volumes, etc.for financial instruments such as stocks; user interface events such asan indication that a user has clicked on a button on a computer display;data entry by a human operator; and computer operating system statuschanges. Virtually any information that is changing over time can betreated as real-time data.

An originator of data may be described as a “data source”. For example,data may originate as a physical process, measured electrically, andconverted to a digital representation, or data may originate in adigital representation. Generally, data is made available in a digitalcomputer as a digital representation, following zero or more steps toconvert the data into a digital representation. A data source maycomprise all of the components and steps necessary to convert the datato a digital form accessible by a computer program.

Analogous to a data source is a “data sink”. A data sink consumes, oruses, data. Some examples of data sinks are: actuators in a processcontrol system; trade processing software in a stock trading system; auser interface application; a database or other data storage system.

Many data sources are also data sinks. Accordingly, a data source maycomprise a data source, a data sink, or both simultaneously. Forexample, when data is transmitted to a data source, the data source mayalso act as a data sink.

In computer applications, data is commonly managed by a “server”. Theserver can act as either a data source or a data sink, or both together,allowing “client” applications to interact with the data that the servermanages.

Generally, a client application must initiate a connection with a serverin order to interact with data. That connection can be “short-lived”,where the connection exists only for the duration of a single or fewinteractions with the data, or “long-lived”, where the connectionpersists for many interactions with the data, and possibly for theduration of the client application's lifetime. Long-lived connectionsare also referred to as “persistent” connections.

Data sources provide data in one or more “data formats” that define thedigital representation of the data. The data format may conform to apublished standard or be particular to the data source. Similarly, datasinks may require data in a published standard format or in a formatparticular to the data sink.

Data sources provide access to data through one or more “transmissionprotocols”. A transmission protocol specifies the mechanism by whichdata are transferred from a data source to a data sink. A transmissionprotocol may conform to a published standard or be particular to thedata source. A data source may combine data formats and transmissionprotocols such that not all supported data formats can be transmittedvia all supported transmission protocols. Generally, a “protocol” or“data protocol” refers to the combination of a particular data formattransmitted via a particular transmission protocol.

A data sink must support at least one data protocol offered by a datasource in order to use the data generated by the data source. Since alarge number of data protocols exist, it is impractical for all datasources and data sinks to support all data protocols. As a result,client applications that make use of data are usually created only tosupport the most necessary protocols for their primary purpose.Similarly, data sources generally support only those protocols that arenecessary for their primary purpose. So, for example, there is no way todirectly connect a web browser that supports the HTTP protocol to aspreadsheet application that supports the DDE protocol.

A protocol conversion step must be performed to convert data from aprotocol supported by a data source into a protocol supported by a datasink in order for the data sink to make use of the data offered by thedata source. This conversion step can be performed by a “middleware”application. A primary purpose of a middleware application may be tofacilitate communication between a data source and a data sink, usuallyby converting data from one protocol to another such that data sourcesand data sinks can interact indirectly when they share no protocol incommon.

A data source may transfer data to a data sink using at least twomethods:

-   -   1. On demand: the data source passively waits for a data sink to        request some or all of the data available in the data source.        When the data sink makes a request for data, the source responds        with a result indicating the current state of the requested        data. If the data sink needs to be informed of changes to the        data, the data sink must repeat the request in order for the        data source to respond with the updated data. This repeated        request for the same data by the data sink is known as        “polling”. A data sink may create either a short-lived        connection to the data source for each new request, or a        persistent connection over which many repeated requests are        transmitted.    -   2. By subscription: the data sink creates a persistent        connection to the data source, and subscribes to some or all of        the data available from the data source. The data source        transmits any changes to the data via the persistent connection        as those changes occur. The data source will continue to send        changes to the data until the data sink specifies otherwise or        the connection is closed.

It is understood that data transfer methods such as shared memory,message queues and mailboxes are variations on either the demand orsubscription methods. It is also understood that the terms datatransfer, data propagation, or data transmission all refer to themovement of data within a system, and these terms may be usedinterchangeably, as they relate to the specific data transfer method. Itis further understood that these methods are independent of theunderlying transmission protocol.

Computer applications dealing with real-time data must be reliable,responsive and easily connected to their data sources. This has meantthat real-time data processing applications have historically beencreated as stand-alone applications connected directly or indirectly tothe data source. This stand-alone architecture has also allowed theapplications to take full advantage of the graphical capabilities of thecomputer to provide rich dynamic visualization of the real-time data. Bycontrast, applications based on web browser technology have provenunsuitable in terms of data connectivity and graphical speed. The HTTPprotocol is intended as a request-response communication method whereeach request-response pair requires a web client (typically a webbrowser) to open a new socket to a web server, perform the communicationand then shut down the socket. This paradigm works well forcommunication that is infrequent and not particularly time-sensitive.The HTTP protocol further limits the types of transactions to dataretrieval from the web server or data submission to the web server, butnot both in the same transaction. Methodologies such as AJAX that arebased on this model are expected to make relatively few transactions andtend to scale to higher speeds very poorly. The computational andnetworking costs of establishing and closing connections for eachtransaction act as a limit to the speed of such systems.

Consequently, widespread real-time data processing, as well as displayin a web browser, has been unavailable. Some developer efforts haveprovided access to data-driven displays using ActiveX components in aweb browser, but these components are generally poorly supported bymodern browsers and subject to limitations due to the security risksthat they represent.

Efforts have been made to display changing data in a web browser usingthe built-in Javascript engine of the browser. This is generallyachieved using a methodology called AJAX (Asynchronous Javascript andXML), where the web browser polls periodically for new data and thenupdates its display accordingly. This polling mechanism is highlyinefficient, and suitable only for relatively small data sets or forrelatively slow-moving data. Lowering the polling rate to conserve CPUor network bandwidth has the effect of raising data latency, which isunacceptable for real-time applications.

Efforts to improve on AJAX, through a mechanism called Streaming AJAX,take advantage of a side-effect of the browser page loading mechanism tocause a browser page to grow incrementally by adding Javascript commandsto the page over time. Each Javascript command executes as it arrives,giving the impression of a continuous data stream. The web browser iseffectively fooled into thinking that it is loading a very large webpage over a slow network connection. This method has several drawbacks,including the fact that the web browser's memory and CPU usage can growcontinuously over time due to the ever-larger page that is beingtransmitted. Holding an HTTP connection open to collect multipleasynchronous messages from a specially designed web server like thiseffectively makes the short-lived HTTP connection into a long-livedstreaming connection. This allows much faster updates from the server tothe client, as new data can be transmitted from the serverasynchronously and does not require the client to open and close aconnection for each new message. However, it does nothing to speed upthe communication from the client to the server. Effectively it createsa fast uni-directional channel from the server to the client, whilestill retaining the negative performance characteristics of HTTP whencommunicating from the client to the server.

Both AJAX and streaming AJAX methods suffer from a lack of qualitydisplay options within the web browser. Web browsers are generallydesigned for the display of static pages and web “forms”, and do notoffer high-speed or high quality graphic presentation options. Effortsto improve upon graphical display options have tended to be incompatibleamong web browsers, and generally very slow to execute.

All data transmission solutions based on built-in web browser capabilityare primarily targeted at receiving data in the web browser. Thecommunication of data is uni-directional, in that the connection thatreceives data from a server cannot also be used to transmit data to theserver. If the web browser needs to transmit data back to the server, itmust do so by opening a new connection, transmitting an HTTP request,and then closing the connection again. Consequently, solutions such asStreaming AJAX are very slow to transmit data back to the data server,because of the large overheads and latencies incurred by having to emita new HTTP request for every data transmission.

Some efforts at web-based data visualization attempt to improve the userexperience by presenting slow-moving (high latency) data as if it werefaster. This is achieved by displaying interpolated data in the webbrowser at higher frequency than the data is actually arriving. Forexample, a circular gauge representing a speedometer might receive thevalues 1 and 100, separated in time by 5 seconds. The web page couldthen draw the gauge dial 5 times per second, changing the value by 4each time. This would give the viewer an impression of a smoothlychanging speed, even though the underlying data delivery contains nosuch information. That is, such a display of interpolated data can beentirely misleading to the viewer. This kind of interpolation obscuresthe true behavior of the underlying data, and is usually unacceptable inreal-time applications such as process control and stock-market trading.

Rich Internet Application (“RIA”) frameworks such as Adobe Flash™ andMicrosoft Silverlight™ offer improved platforms for both data processingand graphical display within a web browser. These RIA frameworks alsosupport direct TCP/IP communications within the RIA. Surprisingly, thecombination of these features makes it possible to process and displayreal-time information in a web browser. This processing and displaycapability has not been translated into real-time data systems due to aperception in the software industry that RIAs are suited primarily tovideo, advertising and games.

A common alternative to HTTP is to provide a secondary communicationsocket for high-speed data alongside the HTTP communication channel.Effectively, the web client communicates via HTTP for the presentationinformation, and via a separate dedicated socket for high-speedbi-directional data communication. This solves the speed issue, butintroduces other issues:

A separate communication socket requires a separate TCP port to be openon the server. This means another opening in the corporate firewall,which IT departments commonly resist.

Rich Internet Application (RIA) frameworks, such as Flash orSilverlight, commonly implement limits on socket communication thatrequire yet another well-known port to be open to act as an accesspolicy server. This introduces a further opening in the corporatefirewall, further limiting the usefulness of the technique.

An RIA framework operating within a browser (e.g., Silverlight) may notimplement its own SSL layer, relying instead on the browser's HTTPSimplementation for encryption. In such a case, a dedicated socketimplemented by an RIA will not be secure.

Dedicated sockets will not pass through web proxies.

The advent of high-speed or real-time data processing over the Internethas created a need for long-lived high-speed socket communication. Thisneed has driven the RIA implementers to offer such sockets, but with thelimitations described above. There remains an unmet need for long-livedbi-directional socket communication over HTTP or, more preferably, HTTPSto a web server.

The HTML5 specification includes a draft specification called WebSockets. This intends to provide two-way communication between a clientand server using a HTTP-mediated socket. Although Web Sockets are notuniversally supported at this time, they provide the possibility ofcreating bi-directional connections through forward and reverse webproxies. The current invention enables real-time data connectivitythrough Web Sockets, providing successful connectivity even in instanceswhere the data source or end user are isolated from the Internet viaproxy servers and are unable to make a connection via an arbitraryTCP/IP port. This significantly broadens the set of network topologieson which the current invention may be usefully implemented whileallowing an additional potential level of security on the clientnetworks.

The present invention is suitable to augment industrial SupervisoryControl And Data Acquisition (“SCADA”) systems. SCADA systems comprisedata collection hardware such as sensors and other devices,communication networks, central processing systems, and display units toallow plant operators and engineers to view the data in their industrialprocesses in real time. SCADA systems often comprise interfaces thatsupport a supervisory level of coordination and control, such asuploading new recipes to a candy-making machine, changing globalsettings on a wind turbine, or acknowledging a high pressure alarm for aboiler.

SCADA systems have evolved over time. The first generation systems were“monolithic”, running on individual computers, connecting to fielddevices directly. The second generation allowed “distributed”processing, using multiple computers communicating with each other overa local-area network (“LAN”) and communicating with the field devicesover proprietary control networks. The current, “networked”, generationuses personal computers and open standards such as TCP/IP and openprotocols for local-area networking. Thus it is now possible to accessSCADA systems and data from the Internet, although there are fundamentalquestions about security that are limiting the broad adoption of suchcapabilities.

Networked SCADA systems are designed using a client/server model. Aserver (device or software application) contains a collection of dataitems. These data items are made available to a client (device orsoftware application) upon request by the client. The implicitassumption is that the server is the authoritative source of the datavalues, and has a-priori knowledge of which data values it will supply.The client is non-authoritative, and determines which data items it mayuse by querying the server. For clarity, the authoritative source ofdata has the responsibility to determine which data items it willcontain and make available to its clients, and the data values held inthe authoritative source are presumed to be correct and current. Theclient cannot determine which data items exist, and may only affect thevalues and/or properties of the data items defined within the server.

Importantly, the server is simultaneously the authoritative data sourceand also a listener for incoming connections from the client. In anetworked system, this means that any client that uses the data must beable to initiate a connection to the server. In a SCADA system, thiswould mean, for example, that an operator workstation (acting as aclient) must be able to make a connection to the SCADA server. This inturn requires that the SCADA server be reachable via the network fromthe client's location. In the case of a Internet-based or cloud-basedsystem, this means that the SCADA server must be reachable from theInternet, posing an unacceptable security risk. For clarity, the terms“cloud” and “Internet” may be used interchangeably throughout thisdisclosure.

When the topic of cloud computing is raised among process controlengineers, there are many justifiable concerns about security. SCADA andother manufacturing and control systems often support high-valueproduction lines, where any interference or foul play could costthousands or millions of dollars. Although recently some shop floorshave begun to make their process data available to the rest of thecompany on corporate LANs, there is strong resistance to opening portsin plant firewalls to allow incoming connections from the Internet.

On the other hand, cloud systems generally require Internet access,typically using a web browser HMI (“Human Machine Interface”) or RIA orother kind of client to connect to a server on the process side. Untilthe present invention, this meant that a port had to be opened in thefactory firewall to allow the web browser to connect. And this is asecurity risk that few plant engineers are willing to take. The primarysource of security exploits is firewalls permitting inbound connections.Unless these are removed, the plant is exposed to attack.

Due to the mission-critical nature of SCADA systems, engineers andmanagers responsible for industrial processes are reluctant to exposethem directly to the Internet, running behind secure firewalls to keepintruders and hackers at bay. Compounding the problem is that thearchitecture of most installed industrial systems was not developed withthe Internet in mind. To adequately address the concerns of industrialusers, a fundamentally different approach to data networking is needed.The present invention solves this problem by employing a novel approachto security that meets the stringent requirements of industrial users ofreal-time data.

SUMMARY OF THE INVENTION

The present invention provides a system and method for use of thegraphical and networking features of network clients such as webbrowsers, RIA frameworks and dedicated applications in conjunction withat least one real-time data server to provide low-latency, real-timedata applications in a web browser. The invention overcomes thelimitations of current AJAX and streaming AJAX while simultaneouslydealing with data sources whose data is not usable within a web browser.

The present invention also provides a long-lived, bi-directionalcommunication mechanism from a web client that may be performed entirelyover HTTP or HTTPS, preferably using existing HTTP verbs (e.g. GET andPOST) while being operable with existing browser and RIA technology.Throughout this disclosure, the terms “RIA”, “Rich InternetApplication”, “Web Browser”, “network client” and “client” areunderstood to refer interchangeably to any software or hardwareapplication that communicates by means of the HTTP or HTTPS protocol.

The present invention also provides a system and method for secure,end-to-end data service enabling real-time data over the Internet. Theinvention provides real-time connectivity between sensors, devices, andmachinery and the users of their data from any remote location that isconnected to the Internet, with data throughput rates that may be over25,000 data changes per second, preferably over 50,000 data changes persecond, more preferably over 75,000 data changes per second, and mostpreferably over 100,000 data changes per second. The added latency ofthe data stream may be measured in milliseconds more than the latency ofthe connection over the Internet itself, preferably no more than 200milliseconds, more preferably no more than 100 milliseconds, yet morepreferably no more than 50 milliseconds, yet more preferably no morethan 25 milliseconds, yet more preferably no more than 10 milliseconds,and most preferably no more than 5 milliseconds. The present inventionis particularly valuable for those working with real-time data fromindustrial systems, embedded devices, “smart” devices or financialsystems.

The invention improves upon the state of the art in real-time datadelivery to web browsers and network clients by reducing the datalatency to a point where visualization components can be animated usingtrue data values, rather than interpolated values. This allowsshort-lived behavior in the data to be more accurately presented to theuser. Short-lived data behavior is commonly important in understandingthe true dynamics of the real-time system represented by that data. Forexample, a person watching a physical gauge can discern important systemproperties by watching vibration or overshoot in the gauge needlebehavior. In one embodiment of the invention, a digital representationof the physical gauge can capture the needle dynamics and provide thesame high-quality information as the physical gauge.

The invention vastly improves the speed of data transmission from theuser to the data server, reducing CPU and network costs and reducinglatency. This allows the user to participate in more sophisticatedcontrol scenarios where system responsiveness is important to correctbehavior. For example, the system may require a hold-and-releaseinteraction while filling a vessel with water. The user would press abutton and hold it until the vessel is full, then release the button.Clearly, the system must respond rapidly in order to avoid over-fillingthe vessel. This type of control is not possible in typical web-basedapplications due to the unpredictability of the data delivery latency.Surprisingly, the invention makes possible classes of control andreal-time data applications that were previously too slow, unreliable orprimitive to be contemplated through a web browser.

Typical web applications deal with data provided in a specific format bythe application designer. This may be an intentional method for limitingthe end-user choice, or simply a limitation on the design. Even wherethe data format follows an industry standard (such as XML or JSON), thedata source is specific to the application. The invention also providesa general purpose mechanism for delivering a wide variety of real-timedata originating from both industry-standard and proprietary sources.Advantageously, the invention can further provide that data in a varietyof data formats.

Many sources of data, both real-time and non-real-time, are not intendedfor network use (i.e., transmission over a network). The presentinvention allows data from these data sources, such as Microsoft Excel™(Microsoft Corp.), to be reliably and rapidly delivered to any RIA orweb-based application over a network. Some data sources, such as thosebased on OPC, were intended for network use but are not designed forcommunication with a web browser. The invention allows these sources toalso be delivered reliably and rapidly to a web-based application. Otherdata sources, such as database systems, provide no interface at all forreal-time information. The invention allows non-real-time data fromsources such as database applications to be delivered as if it werereal-time, thereby eliminating the need for a RIA or web-basedapplication to perform very inefficient polling of the database.

Data sources and data sinks may connect to the server via persistentconnections or short-lived connections. It is understood that theconnection method to the server will reflect the requirements of theparticular data source or sink.

The invention provides a method by which real-time data from one or moredata sources is efficiently made available to a Rich InternetApplication. The invention further provides a method for the RIA toefficiently modify the real-time data or generate new real-time datathat can be transmitted back to the data source or sources. The datasource or sources can then retransmit that data to other RIAs on thenetwork. The invention thus effectively allows any number of RIAapplications to communicate with one another in real time, and tojointly communicate with one or many real-time data sources. Theinvention allows for the abstraction of real-time data such that anydata that can be represented using the abstraction can be made availableto the RIA, regardless of its original source, representation ortransfer protocol.

The present invention provides a system and method for an Internet orcloud-based communication framework and service that does not requireany open incoming firewall ports for connected data sources and clients(e.g. industrial facilities, end-user client devices), therebyeliminating exposure to potential attacks. The invention provides thisnovel improvement by reversing the client/server relationship betweenthe plant and the cloud server. Instead of the plant data source actingas a server, with the present invention, the plant data source acts as aclient, and the cloud service acts as the server. This reverses thedirection of how a connection is made with the Internet. The plant datasource server sends an outbound connection request to a server in thecloud, and therefore there is no need to open any inbound ports in theplant firewall. This novel approach keeps the plant firewall closed, andshrinks the potential attack surface to zero.

Prior to the present invention, reversal of the client/serverrelationship was not done before because there was no perceived need,and it did not make intuitive or architectural sense. Existing SCADA andcontrol systems, as well as standard industrial protocols, such as OPC,expect the server to be an authoritative holder of a data set. Since thedata is being generated at a process, and then used elsewhere, it islogical that consumers of the data (e.g. outside users) are the clients,and that the clients request data from the process, the server. A clientis naturally expected to connect to the server, query the data set, andsubscribe to the data that the client requires. This prior art methodworks well enough in a closed system that existing protocols weredesigned for. However, a cloud-based system requires a fundamentally newapproach.

By changing the role of client and server, the present inventionprovides the unusual and novel case where the client becomes theauthoritative holder of the data set. The process, acting as a client,connects to the cloud server and configures that server with its currentdata set. Updates to the data set are subsequently passed from theprocess to the cloud server. On the other side, users (clients) of thedata connect to the cloud server by a similar method. Clients also makeoutbound client connections to the cloud server, and can interact withthe data set in real time. On the client side as well, no incomingfirewall ports need be opened. Functioning in this manner, the presentinvention allows a cloud server to provide access to process datawithout opening a single incoming port in the plant firewall or in theclient's firewall.

The current invention inverts the client/server relationship. That is,the client application can optionally act as the authoritative datasource, and the server can act as a non-authoritative consumer of thatdata. In fact, the current invention provides for a single applicationto act as an authoritative server, an authoritative client, anon-authoritative server and a non-authoritative client simultaneously.This makes it possible to situate a server application on a publiclyaccessible cloud computer that is acting as a non-authoritative server,while configuring a SCADA system within a secure network as anauthoritative client. The SCADA system makes an outbound connection fromwithin the secure SCADA network to the cloud server, and populates thecloud server with its data set. The cloud server requires no a-prioriknowledge of its data set, but instead learns its data set from theauthoritative client in the SCADA system. Other clients on the publicnetwork that need access to the SCADA system's data will connect to thecloud server as non-authoritative clients, thus treating the cloudserver as an authoritative server for the data that in fact originatesat the SCADA system. Thus, a client application is able to connect tothe cloud system and interact with the SCADA system's data as if it wereconnecting to the SCADA system, yet the SCADA system is never exposed tothe public network. An unexpected result of the present invention is toprovide remote access to the SCADA system's data without compromisingthe network security of the SCADA system itself.

For added security, the current invention allows for a second instanceof the application, operating as a non-authoritative server to the SCADAsystem and as an authoritative client to the cloud system, to beinstalled in a separate network within the industrial plant such thatthis second instance has no access to the secure SCADA network. TheSCADA system then emits data to this second instance, and this secondinstance emits the data to the cloud server. In this configuration, theSCADA system does not even have a direct outbound connection to theInternet, but instead is further isolated by the network containing thesecond instance.

SCADA systems generally provide a mechanism to allow a clientapplication (like an operator panel) to emit value changes to certaindata items. For example, an operator may want to start or stop a machinein the plant. Plant owners may be reluctant to allow modifications tothe SCADA data from remote locations. The current invention allows theSCADA system (acting as an authoritative client to the cloud) to refuseall attempts to modify the values of data items, even where userpermissions would normally allow it. In addition, the cloud server canbe configured to allow certain users to modify the values of certaindata items based on their user credentials and the IP address of thecomputer from which they are connecting. Thus, the current inventionprovides security both from attacks via the public network and fromunauthorized attempts to modify the data, even in the event that thecloud server is compromised.

In another embodiment, a method of providing a secure network connectionis performed by listening at a server for inbound connection requests tothe server on a network between the server and a client, receiving atthe server a first inbound connection request from the client,establishing from the first inbound connection request a first networkconnection between the server and the client, and receiving at theserver a first data set from the client over the first networkconnection, wherein the client is the authoritative source of the firstdata set and is inaccessible via inbound connection requests.

In another embodiment, a system for providing a secure data network isprovided. The system includes a server communicatively coupled to anetwork between the server and a client, the server operable to: listenfor inbound connection requests, establish a first data connectionbetween the server and the client based on a first inbound connectionrequest received by the server, and receive a first data set from theclient over the first data connection, wherein the first data set isproduced by an authoritative source. The client is inaccessible viainbound connection requests and the client is the authoritative source.

Although this description refers to its application to SCADA systems, itshould be understood that this same mechanism is broadly applicable forany data that may be made available via a public network. That datacould originate from any program or process, such as financial tradingsystems, home electricity meters, remote machinery, cell phones,embedded devices, or any other program or device that generates data,and still fall within the scope of the present invention. In one aspectof the invention, a common requirement is that the data source is not berequired to accept inbound network connections in order to make its dataavailable to users of that data.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an exemplary block diagram illustrating a direct connectionbetween a RIA and a data server, in accordance with one embodiment ofthe present invention.

FIG. 2 is an exemplary block diagram illustrating a connection between aRIA, a server, and a separate data source, in accordance with oneembodiment of the invention.

FIG. 3 is an exemplary block diagram illustrating connections betweenmultiple RIAs, a server, and multiple, separate data sources, inaccordance with one embodiment of the invention.

FIG. 4 is an exemplary flowchart illustrating one method of RIA controlflow, in accordance with one embodiment of the invention.

FIG. 5a, b is an exemplary flowchart illustrating one method ofoperation of a server, in accordance with one embodiment of theinvention.

FIG. 6 is an exemplary block diagram illustrating a data server managingsimultaneous connections to multiple RIAs, in accordance with oneembodiment of the invention.

FIG. 7 is an exemplary block diagram illustrating real-time transmissionof data via a local or wide area network between a spreadsheetapplication and a MA, in accordance with one embodiment of theinvention.

FIG. 8 is an exemplary block diagram illustrating a systemimplementation, in accordance with one embodiment of the invention.

FIG. 9 a, b, c is an exemplary flowchart illustrating one method ofoperation of a client and a server, in accordance with one embodiment ofthe invention.

FIG. 10 is an exemplary block diagram illustrating a prior art systemimplementation.

FIG. 11 is an exemplary block diagram illustrating a systemimplementation, in accordance with one embodiment of the invention.

FIG. 12 is an exemplary block diagram illustrating a systemimplementation, in accordance with one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is presented to enable any person skilled inthe art to make and use the invention, and is provided in the context ofparticular applications of the invention. Various modifications to thedisclosed embodiments will be readily apparent to those skilled in theart, and the general principles defined herein may be applied to otherembodiments and applications without departing from the scope of thepresent invention. Reference to various embodiments and examples doesnot limit the scope of the invention, which is limited only by the scopeof the claims attached hereto. Additionally, any examples set forth inthis specification are not intended to be limiting and merely set forthsome of the many possible embodiments for the claimed invention.

The program environment in which a present embodiment of the inventionis executed illustratively incorporates a general-purpose computer or aspecial purpose device such as a hand-held computer, telephone or PLC.Details of such devices (e.g., processor, memory, data storage, display)may be omitted for the sake of clarity.

It is also understood that the techniques of the present invention maybe implemented using a variety of technologies. For example, the methodsdescribed herein may be implemented in software executing on a computersystem, or implemented in hardware utilizing either a combination ofmicroprocessors or other specially designed application-specificintegrated circuits, programmable logic devices, or various combinationsthereof. In particular, the methods described herein may be implementedby a series of computer-executable instructions residing on a suitablecomputer-readable medium. Suitable computer-readable media may includevolatile (e.g., RAM) and/or non-volatile (e.g., ROM, disk) memory,carrier waves and transmission media (e.g., copper wire, coaxial cable,fiber optic media). Exemplary carrier waves may take the form ofelectrical, electromagnetic or optical signals conveying digital datastreams along a local network, a publicly accessible network such as theInternet or some other communication link.

In reference to the example embodiments shown in the figures, it isunderstood that simplified examples were chosen for clarity. Singleinstances of an element (e.g. a RIA, a server, a client, a data source,a data sink, etc.) appearing in the figures may be substituted for aplurality of the same element, and still fall within the scope of thepresent invention.

Accordingly, in one aspect, the present invention provides a method ofproviding real-time data to a RIA, the method comprising: producing dataat a data source; propagating the data to a server; collecting the dataat the server; creating a persistent connection from the RIA to theserver; and subscribing the RIA to subscribed data, wherein thesubscribed data comprises at least some of the data collected at theserver, wherein the server propagates the subscribed data to the RIAthrough the persistent connection as the data is collected at theserver. The method may further comprise sending RIA-originated data tothe server. The RIA-originated data may contain at least one changerequest to the data or at least one command to the server through thepersistent connection. Further, the data may be propagated through atleast one intermediate component. The server may receive the at leastone change request and transmit the at least one change request to thedata source. The at least one change request may be transmitted throughthe intermediate component. The intermediate component may be anintermediate hardware component or an intermediate software component.Optionally, the RIA may subscribe to the subscribed data. Producing dataat the data source and propagating the data to the server may beconcurrent with collecting the data at the server. The RIA may performan action based upon the data, such as a calculation or a modificationof a graphical representation. The RIA may provide a visualrepresentation of the data on a user display, and a user may interactwith the visual representation to generate RIA-originated data. Thevisual representation may be a program running within a RIA framework.The RIA-originated data may instruct the server to perform an action,such as to shut down the server, or to alter its behavior, such as toalter which data arrives from the server.

For example, RIA-originated data may be as a result of user interaction,a timer event, a response to a data change coming from the server, ascript, or another non-user generated event.

In another aspect, the present invention provides a method of providingreal-time data to a RIA, the method comprising: providing data from adata source; propagating data from the data source to a server;collecting data at the server; producing data at the RIA; creating afirst persistent connection from the server to the RIA; creating asecond persistent connection from the RIA to the server; propagatingdata from the RIA to the server through the second persistentconnection; and subscribing the RIA to subscribed data, wherein thesubscribed data comprises at least some of the data collected at theserver, and wherein the server propagates the subscribed data to the RIAthrough the first persistent connection. The method may further comprisepropagating data from the server to a data sink. The first persistentconnection and the second persistent connection may consist of a singleconnection. The data source, data sink and server may consist of asingle component, or any combination of two or more components. The datamay be propagated though at least one intermediate selected from thegroup comprising: a software component, a hardware component, and anetwork.

A data item may be propagated between the RIA and the server on asubscription basis, wherein the data item is propagated immediately inresponse to a change in the data item. The propagated data may beselected from the group comprising: numeric data, non-numeric data,configuration settings and executable commands. The RIA may perform anaction based upon the data, where the action is selected from the groupcomprising: a modification of a visual representation of a user display,a calculation, production of new data, modification of existing data,storage of data, an audible indication, execution of a script,propagation of data to the server, a user-visible programmatic response,and a non-user-visible programmatic response. Data produced at the RIAmay instruct the server to perform an action selected from the groupcomprising: modification of data within the server, propagation of thedata to data sinks connected to the server, execution of a script,storage of the data to a file system, creation of new data, propagationof new data to data sinks connected to the server, modification of aserver configuration, modification of a server behavior, a user-visibleprogrammatic response, and a non-user-visible programmatic response.

In yet another aspect, the present invention provides a computerreadable storage medium storing instructions that, when executed on oneor more computers, cause the computers to perform methods of providingreal-time data to a RIA as described above.

In another aspect, the present invention provides a system for providingreal-time data to a RIA, the system comprising: at least one datasource; at least one server comprising: a data collection component forcollecting data from the at least one data source; and a data emissioncomponent for emitting data to at least one data client; at least oneRIA; and optionally at least one data sink. The server may furthercomprise a data modification component for modifying the form of thedata collected by the data collection component for emission by the dataemission component. It is understood that the at least one data sourceand at least one server may be implemented in at least one computerprogram (i.e. a single computer program, or two or more separatecomputer programs).

The server may further comprise one or more components selected from: adata modification component; a data creation component; a user interfacecomponent; a computer file system interaction component; a programinteraction component for interacting with other programs running on acomputer running the server; a scripting language component to performprogrammable actions; an HTTP component for accepting HTTP requests fromclient programs and respond with documents as specified by thoserequests, in a manner analogous to a “web server”, including the abilityto dynamically construct the document in response to the request, and toinclude within the document the current values of the data resident inthe server and the results of executing statements in the server'sbuilt-in scripting language; a synchronization component to exchange andsynchronize data with another running instance of the server on anylocal or network-accessible computer, such that both servers maintainessentially identical copies of that data, thereby enabling clientapplications connected to either instance of the server to interact withthe same data set; a first throttling component to limit the rate atwhich data is collected; a second throttling component to limit the rateat which data is emitted; a connectivity component to detect a loss ofconnectivity to other servers, and to reconnect to the other serverswhen connectivity is regained; a redundancy component to redundantlyconnect to multiple other servers of identical or similar informationsuch that data from any of the other servers may be collected in theevent that one or more of the other servers is inaccessible; and abridging component to “bridge” data among sources of data such that someor all of the data within those sources will maintain similar valueswith one another, or bridge data among data sources including amathematical transformation such that the data in one source ismaintained as the mathematical transformation of the data in the othersource, including the ability to apply the mathematical transformationin both the forward and inverse directions through a bi-directionbridging operation. It is understood that this set of server componentscould be extended by adding additional functionality to the server tosupport other data collection and transmission mechanisms, otherprocessing mechanisms and other storage mechanisms.

The data collection component may collect data in one or more of thefollowing manners: on demand, wherein the server sends a request forsome or all of the data resident in another server, and that otherserver responds with the current value or values of the requested dataonly once in response to the request; by subscription, wherein theserver sends a request for a subscription to some or all of the dataresident in another server, and the other server responds by sending thecurrent value or values of its data, and then continues to send anysubsequent changes to the value or values of the data until the servereither terminates its connection to the other server, or requests thatthe other server cease sending updates; on a trigger, wherein a client,script or human (a “user”) configures the server to collect the dataonly if a certain trigger condition is met, be that a timer, a time ofday, a data change, a change in the system status, a user action or someother detectable event; and passively by waiting for a “client”application to send data to the server.

The data emission component may emit data in one or more of thefollowing manners: on demand, wherein a “client” application sends arequest for some or all of the data, and the server responds with thecurrent value or values of the requested data only once in response tothe request; by subscription, wherein a client application sends arequest for a subscription to some or all of the data, and the serverresponds by sending the current value or values of the data, and thencontinues to send any subsequent changes to the value or values of thedata until the client either terminates its connection to the server, orrequests that the server cease sending updates; and on a trigger,wherein a client, script or human (a “user”) configures the server toemit the data only if a certain trigger condition is met, be that atimer, a time of day, a data change, a change in the system status, auser action or some other detectable event.

The data collected at the data collection component may be receivedusing one or more transmission protocols selected from: Dynamic DataExchange (DDE), OLE for Process Control (OPC), OPC Alarm and Eventspecification (OPC A&E), OPC Unified Architecture (OPC-UA), OPC ExpressInterface (OPC-Xi), TCP/IP, SSL (Secure Socket Layer) over TCP/IPthrough a custom interface, Hypertext Transfer Protocol (HTTP), SecureHTTP (HTTPS), Open Database Connectivity (ODBC), Microsoft Real-TimeData specification (RTD), Message queues, Windows CommunicationFoundation (WCF), industrial bus protocols such as Profibus and Modbus,Windows System Performance Counters, TCP/IP communication from embeddedsystems, TCP/IP communication from non-MS-Windows systems, TCP/IPcommunication from Linux, TCP/IP communication from QNX, TCP/IPcommunication from TRON, TCP/IP communication from any system offering aC compiler and TCP implementation, Scripts written using a built-inscripting language, data entered by humans through a user interface,data read from a local disk file, data read from a remotely accessibledisk file, proprietary formats, user-defined formats, and formats addedthrough extensions to the server. An example of a proprietary format isWonderware SuiteLink™.

The data emitted from the data emission component may be transmittedusing one or more transmission protocols selected from: Dynamic DataExchange (DDE), OLE for Process Control (OPC), OPC Alarm and Eventspecification (OPC A&E), OPC Unified Architecture (OPC-UA), OPC ExpressInterface (OPC-Xi), TCP/IP, SSL (Secure Socket Layer) over TCP/IPthrough a custom interface, Hypertext Transfer Protocol (HTTP), SecureHTTP (HTTPS), Open Database Connectivity (ODBC), Microsoft Real-TimeData specification (RTD), Message queues, Windows CommunicationFoundation (WCF), industrial bus protocols such as Profibus and Modbus,TCP/IP communication to embedded systems, TCP/IP communication tonon-MS-Windows systems, data presented to humans through a userinterface, data written to a local disk file, data written to a remotelyaccessible disk file, proprietary formats, user-defined formats, formatsadded through extensions to the server, electronic mail (E-Mail), andShort Message Service (SMS) message format.

Further, the data collected at the data collection component may be in aformat appropriate to the transmission protocol. The data emitted fromthe data emission component may be in a format appropriate to thetransmission protocol. The data collected at the data collectioncomponent and the data emitted from the data emission component may alsobe in a format selected from: parenthetical expression (LISP-like)format, Hypertext Markup Language (HTML), eXtensible Markup Language(XML), JavaScript Object Notation (JSON), proprietary binary format,user-definable text format, and a format added through extension of theserver.

The system may further comprise an Application Programming Interface(API) that implements a TCP/IP connection and one or more of the dataformats supported by the server, which may assist a programmer inestablishing a connection as described above. The API may be implementedfor one or more of the following platforms: “C” programming language,“C++” programming language, Microsoft .Net programming environment,Microsoft Silverlight RIA framework, Adobe Flash RIA framework, AdobeAir RIA framework, a programming language supporting TCP/IPcommunication (including any scripting language), and a RIA frameworksupporting TCP/IP communication.

The RIA may be implemented using a RIA framework selected from:Microsoft Silverlight, Adobe Air, and a RIA framework supporting TCP/IPcommunication. The RIA framework may comprise support for: making afirst long-lived TCP/IP data connection to the server to receive data;receiving data from the server; and transmitting data to the server overa second TCP/IP data connection. The data may be received from theserver on demand or by subscription. The first TCP/IP data connectionand the second TCP/IP data connection may be the same connection. Thesecond TCP/IP data connection may be a long-lived connection. The secondTCP/IP data connection may be a short-lived connection. The TCP/IP dataconnection to the server may be in a protocol selected from: an API, asdescribed above, a direct TCP/IP connection, HTTP and HTTPS.

The client may be implemented using a RIA framework, a web browser, acompiled computer language, an interpreted computer language, a hardwaredevice, or another implementation mechanism that supports the HTTPand/or HTTPS protocols. The client may comprise support for: making afirst long-lived TCP/IP data connection to the server to receive data;receiving data from the server; and transmitting data to the server overa second long-lived TCP/IP data connection. The data may be receivedfrom the server on demand or by subscription. The TCP/IP dataconnections to the server may be in a protocol selected from: HTTP andHTTPS.

Data from the server may be received, or data to the server may betransmitted, in one or more forms selected from: a parentheticalexpression (LISP-like) format, Hypertext Markup Language (HTML),eXtensible Markup Language (XML), JavaScript Object Notation (JSON), aproprietary binary format, a user definable format, and a format addedby extension to the server.

The RIA framework may further comprise support for presenting agraphical display representing the data to a user. The graphical displaymay comprise one or more graphical elements selected from: a textualdisplay, a slider, a chart, a trend graph, a circular gauge, a lineargauge, a button, a check box, a radio button, a progress bar, aprimitive graphical object, controls supported by the RIA framework,custom controls created to extend the RIA framework, third-partycontrols implemented using the RIA framework, and a customized graphicalelement.

Configuration information of the graphical display may be saved on theserver, as well as loaded from the server. A graphical element may becreated and modified within the graphical display. The graphical elementmay be a customized graphical element, customizable by a user, whereinthe customization may be saved on the server. Customization may beperformed by a programmer, without requiring modification to anapplication implemented in the RIA framework. The customized graphicalelement may be available for use to a user in other graphical displays.These customizations may be for creating new displays, modifyingexisting displays, all in addition to the graphical elements originallysupported by the user interface application. The graphical element maycomprise one or more properties that are user-modifiable, and which maybe selectable by a programmer. User interaction with the graphicalelement may cause a user interface application to emit modifications tothe data to the server. A user-only mode may be provided to disallowcreation or modification of the graphical display by a user, and aread-only mode may also be provided to disallow interaction with thegraphical element by the user. A system administrator may select whichuser and for which graphical display a user interface application willoperate in one of the user-only mode and read-only mode. The user may berequired to identify himself, and where such identification is required,the user interface application may operate in at least one of theuser-only mode and the read-only mode. Advantageously, the features ofthe invention allow modification of the graphical displays through anyuser RIA terminal and the resulting changes, upon saving, areimmediately available to all other RIA terminals connected to theserver.

In another aspect, the present invention provides a method of providingbi-directional streaming communication over the HTTP or HTTPS protocolbetween a client and a server, the method comprising: generating asession ID; opening a first socket via a first HTTP transaction from theclient to the server; associating the session ID with the first socketat the server and client; opening a second socket via a second HTTPtransaction from the client to the server; associating the session IDwith the second socket at the server and at the client; maintaining along-lived connection on the first socket; and maintaining a long-livedconnection on the second socket, wherein a correspondence is createdamong the session ID, the first socket and the second socket, andwherein bi-directional communication is established between the clientand the server.

The method may further comprise the client transmitting at least onedata message selected from the group comprising: configurationinformation, commands, real-time information, pending data from aprevious transaction, and other data. The method may further comprisewaiting for an event from the first socket; verifying whether the eventfrom the first socket is an error; reading available data from the firstsocket when the event is not an error; processing the data to produce aresult; and optionally sending the result to the server via the secondsocket. The method may further comprise the client: closing the firstsocket; and closing the second socket, wherein the event from the firstsocket is an error. The method may further comprise the client: waitingfor a client-generated event; processing the client-generated event toproduce a result; and optionally sending the result to the server viathe second socket. The client-generated event may be selected from thegroup comprising: an internally-generated stimulus, a result of useractivity, a timer, and an external stimulus. The method may furthercomprise the client: marking data for transmission to the server aspending; closing the second socket; opening a new second socket; andassociating the new second socket with the session ID.

The method may further comprise the server: waiting for an event fromthe second socket; verifying whether the event from the second socket isan error; reading available data from the second socket when the eventis not an error; processing the data to produce a result; and optionallysending the result to the client via the first socket. The method mayfurther comprise the server closing the second socket, wherein the eventfrom the second socket is an error. The method may further comprise theserver: waiting for a server-generated event; processing theserver-generated event to produce a result; and optionally sending theresult to the client via the first socket. The server-generated eventmay be selected from the group comprising: an internally-generatedstimulus, a result of user activity, a timer, a result from anotherconnected client, data from a data source, and an external stimulus. Themethod may further comprise the server: closing the first socket; andclosing the second socket.

In the above method, the first HTTP transaction may be selected from thegroup comprising: a HTTP GET transaction and a HTTP HEAD transaction;and the second HTTP transaction may be selected from the groupcomprising: a HTTP POST transaction, a HTTP PUT transaction, a HTTPPATCH transaction, and a HTTP TRACE transaction. Preferably, the firstHTTP transaction is a HTTP GET transaction, and the second HTTPtransaction is a HTTP POST transaction.

In yet another aspect, the present invention provides a system forproviding bi-directional streaming communication over the HTTP or HTTPSprotocol, the system comprising: at least one client; and at least oneserver, wherein the at least one client is adapted to implement theabove-described method, and wherein the at least one server is adaptedto implement the above-described method. The at least one client maycomprise a RIA. The at least one server may comprises: a data collectioncomponent for collecting data from the at least one data source; and adata emission component for emitting data to at least one data client.

In yet a further aspect, the present invention provides a computerreadable memory storing instructions that, when executed on one or morecomputers, cause the computers to perform a method of providingbi-directional streaming communication over the HTTP or HTTPS protocolbetween a client and a server, the method comprising the steps of theabove-described method.

As described above, the HTTP protocol implements a transaction modelwhere each transaction is generally short-lived. Each transaction isinitiated by the client, and is specified to either transmit data to theserver, or to request data from the server, but not both.

A web client may need to transmit or receive a large volume of data. Inthis case, it may implement an API that allows the client tosend-and-receive the data in incomplete chunks. That is, it may requiremultiple send and receive actions before the entire data set has beentransmitted. For example, a client that receives an image from a servermay receive the image in chunks of 1 KB so that it can begin to renderthe image before the entire image has arrived to produce a progressiverendering effect. This behavior can be leveraged within the client toproduce a continuous stream of data. The client may make an HTTP GETrequest to a URL on a specially designed server (or a standard serverwith a specially designed handler for that URL). The server may respondwith an HTTP header, and then hold the socket open. At any time in thefuture, the server may transmit data on the socket, which will arrive atthe client as an incomplete transmission. The client can process thisdata and then wait for more. So long as the server holds the socketopen, the client will simply act on the expectation that there is moredata to be received, and will process it as it arrives. The server cantransmit more information asynchronously to the client at any timewithout the need for the client to repeatedly open and close HTTPconnections. This mechanism is the underlying methodology of StreamingAJAX. As disclosed above, it is uni-directional. This mechanism does notprovide high-speed communication from the client to the server.

One of the important innovations of the present invention is to solvethe problem of creating a high-speed connection from the client to theserver. The solution provides that the client opens an HTTP POSTtransaction with the server, and transmits the necessary HTTP headerinformation. The server will then wait for the data payload of the POSTto arrive. At any time in the future, the client may transmit data onthe open socket, effectively acting like the Streaming AJAX mechanism inthe reverse direction. The client may hold the socket open indefinitely,transmitting data as necessary without having to repeatedly open andclose HTTP connections for each new transmission.

The server must be aware that the data will arrive as a stream, and toprocess the information as it arrives. This may require custom behaviorin the server.

The HTTP protocol specifies that a client must inform the server of thesize of an HTTP POST message in the HTTP headers (the content-length).It is a violation of the HTTP protocol for the client to transmit moreor less data than specified in the content-length header. The presentinvention recognizes this by tracking the number of bytes transmittedfrom the client to the server. The HTTP POST content length is specifiedby the client to be an arbitrary number of bytes. When the client hastransmitted content-length bytes, it closes its existing connection andopens a new connection and continues transmitting. The number of bytesin a POST message can be large (e.g. up to 2³¹ bytes), so this open andclose will happen very infrequently. The result will be a slight latencyin the transmission of some data, but no loss of information.

In a preferred embodiment, the present invention requires two sockets,one handling the server-to-client communication via HTTP GET, and theother handling client-to-server communication via HTTP POST. In orderfor these two sockets to act in concert to provide bi-directionalstreaming communication, the web server must be aware that they arerelated halves of a single conversation. This relationship may beestablished by the client. The client opens the HTTP GET connectionfirst, and includes in its URL a unique session handle (e.g., a randomlygenerated GUID). When the client subsequently opens the HTTP POSTrequest, it includes the same session handle in the URL. The server isthen able to associate the two connections. When the HTTP POSTconnection must be closed and re-opened due to reaching thecontent-length limit, the client transmits the same GUID again. Theserver is then able to associate this new POST socket with the existingGET socket.

The web server needs to understand that this methodology is beingemployed. It must keep track of calls to a specially designated URL forthe original GET connection, associate the session handle with thatconnection, and then subsequently associate POST connections with thesame session handle with that GET connection. It may be desirable, butnot necessary, for the web server to spawn a separate thread to handleeach connection pair.

Having established the GET and POST connections, the client can receiveasynchronous data transmissions from the server via the GET connectionand transmit asynchronous data to the server via the POST connection.The server does the reverse, transmitting data via the GET connectionand receiving data via the POST connection. The behavior of both clientand server are otherwise the same as if they were communicating via asingle bi-directional socket.

As will be understood by a person skilled in the art, other HTTP verbssuch as HEAD, PUT, PATCH and TRACE may also be used. It will also beappreciated, for example, that it is possible to further modify a serverto recognize other verbs or relax protocol restrictions on the HEADtransaction to behave like a GET. So, other verbs may be used if theserver is modified to recognize the added/different behavior. Suchmodifications depart from a strict implementation of the HTTPspecification, yet still fall within the present invention.

The unexpected advantages of the present invention in regard to thesystem and method for secure real-time cloud services are several. Toaddress security concerns, one prior art method for sharing process dataon the cloud has been to use a Virtual Private Network (“VPN”). However,from a security perspective, use of a VPN is problematic because everydevice on the VPN is open to every other machine. Each device (and eachuser of said device) must be fully trusted on the VPN. Security iscomplex and not very good, making it virtually impossible to use thisapproach for open communication between companies. Accordingly, thepresent invention allows sharing of data between third party companieswithout requiring that the third parties access an existing VPN, andtherefore never exposing computers and devices on the VPN to those thirdparties. Furthermore, VPNs also incur a performance penalty, eithercompromising real-time performance or significant additional cost tocompensate (e.g., by requiring additional hardware, computationalresources and complexity to a system).

Further advantageously, the present invention allows users to connectplant floor equipment to management as well as partner and third-partycompanies, using software at the plant site that is configured by theclient company to allow specific data streams to be uploaded ordownloaded.

The present invention may be completely software-based, and can beimplemented on existing hardware, therefore not introducing significantcomplexity to an established network.

Advantageously, using methods disclosed herein, once the client/serverconnection is established, the data can flow in either direction. Clientusers can monitor a system in real time, affect changes, and see theeffect of their actions immediately, as if they were working on a localsystem. Or, if required, the system can be configured from the plant tobe one-way, read-only.

The present invention provides the ability to connect to any industrialsystem, using open, standard protocols like OPC, TCP, and ODBC. Suchflexibility allows further cost reduction by fully utilizing investmentsin existing equipment, or enhance new installations with cloudconnectivity. Examples uses of the present invention are the addition toexisting SCADA systems, enhanced function as an HMI for an individualmachine, or access RTUs or even individual embedded devices.

In combination with methods disclosed herein, the present inventionsupports publish/subscribe data delivery, an event-driven model in whicha client registers for data changes one time and then receivessubsequent updates immediately after they occur. This low-latency,cloud-based system adds extremely low overhead to the overall datatransmission time, effectively keeping throughput speeds to just a fewmilliseconds (or less) more than the network propagation time.

In one embodiment, the present invention may achieve very high-speedperformance is by handling data in the simplest possible format.Providing a data-centric design, the present system can function withvarious kinds of data sources and users, such as control systems, OPCservers, databases, spreadsheets, web pages, and embedded devices.Preferably, when a connection is made to the cloud server, incoming datais stripped of unnecessary formatting (XML, HTML, OPC, SQL, etc.) andpassed as quickly as possible to any registered clients. At thereceiving end the data is delivered in whatever format the clientrequires.

With the methods disclosed herein, a RIA or web-based user interface forsecure cloud services provides anywhere-access to register for theservice, configure data connection options, and monitor usage and costs.Additionally, all data display screens may be provided via the web-basedinterface. This web-based HMI allows users to create pages fromanywhere, and deploy them immediately.

Further advantageously, one of the benefits of cloud computing is itsability to scale up or down to meet the needs of its users. The presentinvention can not only handle bursts of high-speed activity in the dataflow, it can also be quickly configured to meet the needs of a growingsystem. Users can add data points to a particular device, or bring onnew devices, new SCADA systems, even new locations and installationsthrough an easy-to-use, web-based configuration interface.

The present invention is operable as a real-time industrial system, andcan maintain a suitable level of performance and security in a cloudenvironment. Its sophisticated connectivity options allow the primarycontrol system in a plant to continue functioning without disruption.The result is a robust and secure feed of live process data into anenterprise to provide opportunities for real-time monitoring,collaboration, and predictive maintenance.

Referring to FIG. 1, in one embodiment, RIA 101 makes a data connectiondirectly to a program that is acting as both data source and data server100. This could occur where the data source is both a collector of rawdata and a transmitter via a TCP/IP protocol. An example of this wouldbe an OPC-UA server embedded within a PLC. Another example would be anembedded device that acts as a data source and provides a TCP/IP servercapability offering a custom TCP/IP interface. Yet another example wouldbe a stock market data feed that offers a TCP/IP interface.

Referring to FIG. 2, in one embodiment, another configuration comprisesa separate data source 202 and server 203. This configuration extendsthe communication model by converting the data protocol of data source202 into a TCP/IP protocol that can be processed by RIA 201. Thisgreatly broadens the number and type of data sources 202 by allowing theserver 203 to interact with data sources 202 that do not provide aTCP/IP interface directly.

Referring to FIG. 3, in one embodiment, server 303 may manageconnections to more than one data source 302 and to more than one RIA301 simultaneously. This more complex configuration performs aggregationof data from data sources 302 and RIAs 301 into a single data set thatis accessible from anywhere on the TCP/IP network.

In another embodiment, a system may include multiple servers,interconnected with one or more data sources and/or one or more RIAs.

Referring to FIG. 4, in one embodiment, a method of RIA behavior andcontrol flow is shown. The RIA does not require an explicit stoppingcriterion, though one or more may be incorporated. The RIA is stoppedimplicitly when a user closes the web browser or page containing theRIA. The RIA simultaneously follows two flows of control, which can beeither interleaved in a single program thread or implemented in separateprogram threads. The method may comprise additional processing specificto the RIA.

In the first flow of control, the RIA attempts to establish and maintaina connection to a server, and to respond to changes in the dataavailable from the server. The RIA first attempts to establish aconnection (Step 401). If the connection is not successful, it simplyre-tries that connection indefinitely. If the connection succeeds (Step402) then the RIA may subscribe to all or part of the data set (Step403). Alternatively, it is possible for the server to implicitlysubscribe the RIA to the data set based on the presence of a connection,in which case Step 403 may be skipped. In addition to a subscription,the RIA may also transmit other information to the server to configurethe behavior of the data transmission, such as a minimum time betweenupdates or timeout parameters on the connection.

Having once established a connection, the RIA waits for notifications ofa change in data from the server (Step 404). If a data change hasoccurred (Step 405) then the RIA processes that data in some fashion(Step 407). This processing may be to modify an internal state of theRIA, modify a graphical representation, play a sound or any otherprogrammatic response that the RIA designer determines. If no datachange occurs, the RIA checks to determine if the connection to theserver has been lost for any reason (Step 406). If the connection hasnot been lost, the RIA returns to wait for a data change to occur (Step404). If the connection has been lost then the RIA re-tries theconnection to the server (Step 401).

Simultaneously with Steps 401 through 407, the RIA may also accept userinput, allowing the user to generate changes in the data that can bepropagated back to the server. The RIA waits for user input (Step 420)either in a separate program thread or multiplexed with Steps 401through 407.

FIG. 4 exemplifies a separately threaded method. If user input hasoccurred (Step 421) then the RIA can attempt to transmit the resultingdata to the server. It does this by first checking to see if the serveris connected (Step 422). If so, the RIA transmits the new data to theserver (Step 423). If not, the RIA waits for more input (Step 420). Thecheck for the server connection (Step 422) may be implicit in theattempt to transmit the data, in which case Steps 422 and 423 arecombined in practice.

The RIA may also be non-interactive such that user input is notaccepted, in which case Steps 420 to 423 can be omitted.

Referring to FIG. 5, in one embodiment, the method of operation of adata server is shown. The server may be simultaneously collecting datafrom zero or more data sources while serving data to zero or more RIAconnections. The two main flows of control can be implemented inseparate threads, or by interleaving the two flow control paths within asingle thread.

In order to interact with a data source, the server must first establisha connection to that data source (Step 501). Normally, the serverinitiates this connection to the data source. In some cases, the datasource may initiate the connection to the server. If the connectionsucceeds (Step 502), the server begins collecting data from the datasource (Step 503). If the connection fails, the server re-tries theconnection to the data source (Step 501). If the data source is theinitiator of the connection to the server, then Steps 501 and 502collapse to a single wait state and the server passively waits for thedata source to connect. The data collection (Step 503) will follow amethod appropriate to the data source, and may differ from one datasource to another. The server can be made to accommodate any data sourcewhose data can be represented in the server. If new data becomesavailable from the data source (Step 504), the server converts that datato the server's internal data representation. This allows the server toaggregate data from a variety of data sources using different datarepresentations. Step 506 can be omitted in the simple case where thedata source, server and RIA all use the same data representation. Theserver then attempts to transmit the data to each RIA. The server mayfirst establish that a RIA is connected (Step 507). If one or more RIAsare connected, the server converts the data to a representation suitablefor the RIA (Step 508) and transmits that data to each connected RIA(Step 509). If no RIA is connected, the server continues collecting datafrom the data source (Step 503). The server repeats this sequence (Steps501-509) indefinitely. The server may choose not to collect data from adata source when no data sink is connected to the server that requiresdata from that data source.

Simultaneous with, or interleaved with, collecting data from the datasource, the server also manages connections from RIAs. The server waitsfor a connection from an RIA (Step 520). When an RIA attempts to connectto the server (Step 521) the server accepts the connection (Step 522)and continues to wait for connections from other RIAs. While waiting foran RIA to connect, the server must also determine whether an existingRIA connection has disconnected (Step 523). If an RIA has disconnected,the RIA connection is removed from any tracking in the server (Step 524)so that no attempt is made in future to transmit data (Step 509) to thedisconnected RIA. The server repeats this sequence (Steps 520-524)indefinitely. The server may apply acceptance criteria when the RIAattempts to connect (Step 522) such that the server may refuse theconnection for any reason, such as an authentication failure or aserver-applied limit on the maximum number of concurrent connectionsfrom RIA instances.

Simultaneously with, or interleaved with, collecting data from the datasource and managing new connections from RIAs, the server may alsoreceive data from RIAs already connected. The server waits for data toarrive from the RIA (Step 530). When new data arrives (Step 531), theserver converts this data into the server's internal data format (Step532). The server then determines if any RIA is currently connected (Step533). The server then converts the data to a format suitable for receiptby the RIA (Step 534) and transmits the data to each currently connectedRIA (Step 535). The server then determines if any data source thatrequires this change of information is currently connected (Step 536).For each data source requiring the information that is currentlyconnected to the server, the server converts the data to a formatsuitable for that data source (Step 537) and transmits the data (Step538). The server repeats this sequence (Steps 530-538) indefinitely.

Steps 501 through 509 can be replicated repeatedly for each data sourceto which the server may connect.

Steps 520 through 524 can be replicated repeatedly for each RIA fromwhich the server may receive a connection.

Steps 530 through 538 may be replicated for each connected RIA, or maybe multiplexed such that Step 530 waits simultaneously for all connectedRIAs at once, or any combination of these options.

It is understood that the methods exemplified in FIG. 4 and FIG. 5 maybe modified to include additional capabilities, including: explicitstopping conditions for both the RIA and the data server; the ability ofthe server to wait passively for a data source to connect to the server;the ability of the server to actively connect to the RIA; the ability ofthe server to simultaneously manage connections to multiple datasources; the ability of the server to simultaneously manage connectionsto multiple RIAs; and the ability of the server to simultaneouslyreceive data from multiple RIAs.

Referring to FIG. 6, in one embodiment, the data server's 603 ability tosimultaneously manage connections to multiple RIAs 601 advantageouslyallows for RIAs 601 to communicate among one another through the server.Any information transmitted from RIA 601 to server 603 will be treatedby the server as if the RIA 601 is a data source, and will propagatethat data to any other RIAs 601 that are connected to the server andhave subscribed to that data. Surprisingly, this effectively creates anetwork of RIAs intercommunicating in real time. In fact, server 603 maybe used to enable communication among any number of client applications,using any combination of protocols that the server supports.

Referring to FIG. 7, in one embodiment, a substantial benefit of thisinvention is the ability to present data in RIA 701 that originates fromsources that cannot otherwise be accessed via a network. In thisembodiment, data originating in spreadsheet application 705, such asMicrosoft Excel, may be transmitted via a local or wide area network,which was not possible prior to the present invention. Data transmissionfrom Microsoft Excel is limited to DDE, RTD or ad-hoc communicationthrough fragile scripts. No protocol supplied by Microsoft Excel,including DDE, RTD and ad-hoc communication through scripts, enablesreal-time communication with a RIA. The invention allows any applicationto communicate in real time with the spreadsheet data over any TCP/IPnetwork, vastly broadening the scope of applications for spreadsheetdata. The combination of this communication ability with RIA 701 offersthe ability to have multiple simultaneous users interacting with asingle spreadsheet through a simple web browser connection. This samefunctionality extends to any protocol that server 703 supports.

When running a RIA within a web browser, the RIA must be served to a webbrowser using a web server. That is, the user enters a URL into a webbrowser, or clicks a link within a web page for that URL, causing theweb browser to load a web page containing the RIA. The URL is servicedby a web server such as Microsoft IIS™ or Apache™. The sequence ofevents when loading and connecting the RIA is thus:

1. The user selects a URL in the web browser

2. The web browser loads the page containing the RIA from the web server

3. The web browser starts the RIA

4. The RIA connects to the data server via TCP/IP

5. The RIA subscribes to data in the data server

6. The data server begins transmitting data according to thesubscription

7. Data service continues until the RIA disconnects or is otherwisestopped

This sequence requires that a web server be present and configured toserve the RIA. It may be convenient to embed the web server capabilitywithin the data server to reduce the number of system components and tomore tightly integrate the web functions with the data functions of theRIA.

It will be readily apparent to those skilled in the art that the RIA maybe executed from an embedded browser or a separate non-browser host(sometimes referred to as an out-of-browser mode for the RIA) to launcha RIA session. The URL and web browser may not be evident to the user.Accordingly, the first three steps in the sequence of events above maybe modified to reflect these alternate embodiments.

In the present invention, a RIA may be any application written using aRIA framework that is capable of using or generating data.

In one embodiment, the RIA displays real-time data visually to a user.The visual components may be gauges, trend graphs, progress bars,buttons, images and other visual representations common in desktopapplications. Since there is a wide variety of possible representations,and the most suitable representation for a particular data set willdiffer from the most suitable representation for another data set, theRIA should be user-configurable. This means that the user may bepresented with a visual configuration tool that allows him to associatedata with visual “objects”. A collection of these visual objects can bearranged together into a visual “page” commonly used to display relatedinformation. The user could then create multiple pages to displaydifferent sets of related information.

In order to provide to the user the ability to customize the datavisualization, the RIA must provide either integrated or separatecustomization functionality, more commonly referred to as an editor.This editor provides a means by which the user specifies the visualdesign of pages displaying the real-time data. The editor may alsoprovide the ability to design specialized versions of visual objects.

The information regarding the design of individual visual objects andthe design of the visual pages should be stored by the web server. Thisallows the user to create data visualization that can be viewed by anyother user with the necessary access privileges at the web server. TheRIA interacts with the web server to store and retrieve documents storedin a format such as XML. The transmission of this information may beperformed either through an existing real-time data connection or usinga separate HTTP connection. A built-in web server within the data serversimplifies the implementation of this transmission, but is notnecessary.

In one embodiment of the invention, a system implementing the methods ofthe invention comprises the following software applications:

-   -   1. Cogent DataHub™ (Cogent Real-Time Systems Inc.) acting as the        data server    -   2. Cogent DataHub (Cogent Real-Time Systems Inc.) acting as the        web server    -   3. Microsoft Silverlight (Microsoft Corp.) acting as the RIA        framework    -   4. DataHub API for .Net (Cogent Real-Time Systems Inc.) acting        as a protocol implementation layer for Microsoft Silverlight    -   5. DataHub WebView™ (Cogent Real-Time Systems Inc.) acting as a        RIA for display of real-time data in a web browser    -   6. DataHub WebView (Cogent Real-Time Systems Inc.) acting as a        display editor for visual object and page design

In addition, Cogent DataHub may send and receive data from a variety ofdata sources, including:

-   -   1. Microsoft Excel™ (Microsoft Corp.) acting as a spreadsheet        application    -   2. OPC-DA server (various manufacturers) acting as a data        communication interface    -   3. OPC-UA server (various manufacturers) acting as a data        communication interface    -   4. OPC Xi server (various manufacturers) acting as a data        communication interface    -   5. ODBC server (various manufacturers) acting as a database        interface

Referring to FIG. 8, in one embodiment, depending on the particularimplementation, zero or more data sources 801 are attached to the CogentDataHub™ 802, which in turn is attached to a Cogent DataHub WebView™ RIA803 for delivering real-time data displays.

In alternate embodiments of the invention, the RIA framework may be anyRIA framework capable of supporting a persistent network connection.Examples of alternate such RIA frameworks include Adobe Flash™ and AdobeFlex™. It is appreciated that other RIA frameworks may also be suitable.

The RIA may be any application created using the RIA framework that canconsume or produce data using the server's TCP/IP communicationprotocol.

The RIA framework could be integral to the web browser, as would be thecase, for example, if HTML5 supported the necessary TCP communicationmechanism.

The data server may be any application designed to collect data from adata source or act as a data source itself, as long as it also suppliesa TCP/IP communication method that can be accessed by a constructed RIA.

A data source may be any application or system capable of producingreal-time data that can be converted into a format suitable forrepresentation within the server.

A data source may also be any application or system capable of producingnon-real-time data that can be converted into a format suitable forrepresentation within the server. The server can poll this datarepeatedly or collect it by subscription to provide the data to a RIAeven in the case that the original data is not real-time. For example, adatabase management system (DBMS) is generally not real-time, but thedata can be polled repeatedly to create a periodically updating data setwithin the server, thus supplying a RIA with a pseudo-real-time view ofthe data within the DBMS.

The server and the data source may be combined into a singleapplication, as may be the case with an OPC-UA server, or with anembedded device that offers access to its data via a TCP/IP connection.

The web server may be any application capable of serving the web pagecontaining the RIA.

A program developed using any compiled or interpreted computer languagethat can open and interact with a TCP/IP socket may be used in place ofa RIA, which may or may not run within a web browser. Similarly, themethods of the present invention may also be implemented using codeexecutable directly in a browser, in an out-of-browser host, or throughan extension of the browser, in place of a RIA, such that the browser,out-of-browser host, or browser extension can open and interact with aTCP/IP socket, make a persistent network connection and, optionally,offer graphical capabilities.

Referring to FIG. 9, in one embodiment, a mechanism for bi-directionalstreaming communication between a client and a server using two HTTPconnections is shown. It is assumed that the server is already running,and is listening for TCP connections on a port agreed upon by the serverand the client. For clarity, specifics of the HTTP protocol are notshown or described, as that is well-defined in the industry, and knownto a person skilled in the art. Also, the handling of immaterial errorconditions is omitted.

As shown in FIG. 9a , the client starts, or begins, its attempt tocommunicate with the server via bi-directional HTTP streaming (Step900). First, the client generates a GUID to identify the presentcommunication session (Step 901). Alternatively, the server couldgenerate a GUID at the client's request (not shown). This GUID will beused by the server to associate the GET and POST sockets with oneanother and with the client connection. Next, the client opens an HTTPGET transaction, supplying its GUID as part of the URL (Step 902). Theserver records this GUID and associates it with the HTTP GET socket(Step 903). The server holds this socket open. The client then opens anHTTP POST transaction with the server (Step 904), again supplying theGUID as part of the URL, or in the body of the POST message. The clientspecifies the content-length of this HTTP POST transaction to be anarbitrary number of bytes that is acceptable to the server. The serverassociates the HTTP POST socket with the GUID, therefore creating acorrespondence among the client, the POST socket and the GET socket.

Once the POST and GET sockets have been successfully opened, the clientmay transmit configuration information and any data pending from aprevious connection via the POST socket (Step 906). The client maychoose to send configuration information only on the first connection ofthe POST socket for a given session. On subsequent POST socketconnections, there may be data that was previously undeliverable that isdelivered at this point. If any commands or data were transmitted inStep 906, then the server processes them (Step 907) and generates zeroor more responses that the client will receive in Step 908.

Once the connection is fully established, the client and serverrespectively enter wait states where they wait either for data arrivingfrom the other, or for events that would cause them to emit data to theother. That is, the server may wait for data to arrive from the client,or for a locally generated (server-generated) event to occur (Step 919),as illustrated in FIG. 9c . Similarly, the client may wait for data toarrive from the server, or for a locally generated (client-generated)event to occur (Step 908), as illustrated in FIG. 9 b.

Referring to FIG. 9b , the client will subsequently enter a loop whereit waits for an event (Step 908) and processes it according to its type(Step 909). If the event is an event originating from the GET socket,the client will first check whether that event is a socket error (Step911). If so, the client closes its end of the GET and POST sockets (Step915), effectively closing the communication session with the server, andtries to create a new session with the server by returning to Step 902,or alternatively to Step 901 (not shown). If the event is an eventoriginating from the GET socket and is not an error, the client readsthe available data from the socket (Step 912), and processes it in somemanner (Step 913). This processing may generate a result that can betransmitted back to the server via the POST socket (Step 914). Theresult may be a nil result, in which case nothing is transmitted back tothe server. Alternatively, the client may optionally choose to transmitnothing back to the server.

The result transmission via the POST socket in Step 914 could fail. Atleast one failure mode is an HTTP protocol violation. That is, once theclient has transmitted content-length bytes to the server, it is aviolation of the HTTP protocol to send more bytes on the POST socket.Subsequent attempts to send data on the POST socket will fail, so theclient checks for this and other failures (Step 916). If a transmissionfailure occurs then the client will mark the data for this transmissionas pending (Step 917), and will close the POST socket (Step 918). Theclient will then attempt to re-open the POST socket by returning to step904. In this instance, the client should not close and re-open the GETsocket, since that would terminate the entire session and would causethe pending transmission to be lost. By re-opening the POST socket, theclient and server maintain their session even though a socketreconnection is taking place.

If the client generates an event internally, or as a result of useractivity, a timer, or other external stimulus that requirescommunication with the server in Step 909, then the client will performwhatever processing is required to compute data to be transmitted to theserver (Step 910). This data is effectively the result data of theevent, which is then transmitted to the server (Step 914) and followsthe same transmission method as for result data from a socket event.

The client may loop indefinitely, establishing the connection to theserver and re-establishing that connection should it fail. The clientmay choose to signal failures and reconnection states to a user or otherprogram, or may simply reconnect to the server without notification.

After Step 907, the server will also enter a loop where it waits for anevent in Step 919 and processes it according to its type (Step 920), asillustrated in FIG. 9c . If the event is an event originating from thePOST socket, the server will first check whether that event is a socketerror (Step 922). If the event is a socket error, the server closes itsend of the POST socket (Step 923), effectively requesting that theclient re-establish its POST socket. This allows the client to maintainits session with the server by only re-establishing one of the twocommunication sockets. If the event is an event originating from thePOST socket and is not an error, the server reads the available datafrom the socket (Step 924), and processes it in some manner (Step 925).This processing may generate a result that can be transmitted back tothe client via the GET socket (Step 926). The result may be a nilresult, in which case nothing is transmitted back to the client.Alternatively, the server may optionally choose to transmit nothing backto the client.

The resultant transmission via the GET socket in Step 926 could fail.The server checks for transmissions failures (Step 927), and if atransmission failure occurs then the server will close both the POST andGET sockets, effectively ending the session (Step 928). The server doesnot attempt to re-establish a connection with the client, but ratherwaits for the client to re-establish the connection if necessary. Thiseffectively will return the client/server system to Step 902 or,alternatively, to Step 901 (not shown). It may be desirable in someimplementations to maintain the same GUID through multiple sessions,although this is not a required feature.

If the server generates an event internally, or as a result of useractivity, a timer, another connected client, data from a data source, orother external stimulus that requires communication with the client inStep 919, then the server will perform whatever processing is requiredto compute data to be transmitted to the client (Step 921). This data iseffectively the result data of the event, which is then transmitted tothe client (Step 926) and follows the same transmission method as forresult data from a socket event.

As would be readily appreciated by a person skilled in the art, therecan be errors handling in Steps 901 through 907 that would close anyopen sockets and re-start the connection process at Step 901. Althoughthese errors handling have not been illustrated in FIG. 9 for clarity,they would be included in a preferred embodiment. As will be appreciatedby a person skilled in the art, the client may choose to terminate theconnection (e.g. closing the browser client), and any such terminationmay be handled by the server in the same manner as a transmission error.That is, the server will close both the GET and POST sockets, terminatethe session and wait for a client to connect (Step 900).

The client and server can implement wait states in any number of ways,including creating a new process thread to perform a synchronous wait orperforming a multiple-event wait in a single thread. These areimplementation details that will depend on choices made during theclient and server implementations, but do not depart from the scope ofthe present invention.

Surprisingly, a substantial benefit of the present invention is theability to provide high-speed, bi-directional communication between aclient and server using a HTTP or HTTPS-mediated socket, whileovercoming limitations in the HTTP protocol, and also maintainingoperability with existing browser and RIA technology.

In an alternate embodiment, the present invention and the bi-directionalcommunication method is also applicable to web client/servers employinga RIA.

Advantageously, the present invention is operable on any device that iscapable of opening an HTTP or HTTPS-mediated socket. For example, theclient/server implementation may comprise multiple servers propagatingdata in real-time over a network or the Internet, optionally in a securemanner via HTTPS, without any major and therefore costly changes inexisting infrastructure (e.g., security policies, firewalls, software,hardware, etc.).

Referring to FIG. 10, a prior art system for providing directcommunication between a server 1002 and a client 1001 separated by anetwork 1007 is shown, as envisioned by a traditional SCADA system. Inthis example implementation, the server 1002 and client 1001 aresituated behind firewalls 1003, 1004 to protect from unauthorized accessfrom any third parties (not shown) on network 1007. Arrow 1006symbolically shows client 1001 originating a request for data located onserver 1002, and arrow 1005 shows server 1002 waiting for incomingrequests from client 1001. In order for the client 1001 to access dataon server 1002, the server's firewall 1003 must be configured to allowan incoming connection from outside firewall 1003. In this example,server 1002 is exposed to incoming requests originating from network1007, and therefore firewall 1003 provides a point of attack orvulnerability that may be exploited.

When the network 1007 is a private network, the assumption is that aconcerted malicious attack on the server 1002 through the open port onthe firewall 1003 is unlikely and an acceptable risk. However, when thenetwork 1007 is a public network (e.g. the Internet), the likelihood ofa concerted attack on the server 1002 is high, and the risk isunacceptable.

Referring to FIG. 11, in one embodiment, a system for providing secure,real-time data over a network 1107 is shown. In contrast to the priorart system shown in FIG. 10, the novel system shown in FIG. 11illustrates the differences between a direct client/server connection,and a cloud-based system as provided by the present invention.

In the present invention, a cloud server 1100 is situated away from boththe server 1102, acting as an authoritative client, and the user client1101 (non-authoritative). Both the server 1102 and client 1101 initiateoutbound connections, as shown by arrows 1105, 1106, to the cloud server1100, through their respective firewalls 1103, 1104. The firewalls 1103,1104 are not required to provide any open inbound ports. Thisconfiguration is equally secure regardless of whether the network 1107between server 1102 and client 1101 is private or public.

The server or authoritative client 1102 decides what data to send to thecloud server 1100. Further, each server 1102 can set each data stream tobe one-way or two-way, and can send some or all of its data, dependingon its needs. Preferably, this configuration is set by the customer atthe authoritative client by way of a connector, provided in the form ofa software application described above (the DataHub). Accordingly,configuration may be set entirely in the connector, not at the cloudserver, thereby optionally providing an additional layer of securityshould the cloud server be compromised.

Also shown in FIG. 11 are multiple servers 1102 acting as authoritativeclients, which is an unexpected result made possible by the presentinvention. Specifically, the present invention allows multiple servers1102 to act as authoritative clients for their own data sets (notillustrated), and aggregated at the cloud server 1102 for efficientconsumption by one or more clients 1101. Surprisingly, this allows forservers 1102 to be located in physically separate locations from eachother (e.g. in different plant facilities located around the world),while producing a unified data set at the cloud server such that theclient(s) 1101 see the unified data set as if it were produced from asingle system. That is, distributed system appears to the client as asingle system. Such functionality is not possible in traditional SCADAsystems. This is advantageous at least to provide convenience and theability to simultaneously monitor an entire network of systems, and toshare data among the servers 1102. Examples of such applications arebroad, for instance coordinated operation of vehicle fleets, networks ofdevices, global financial trading systems and redundant parallelsystems.

When an authoritative client (server 1102) connects to the cloud server1100, it does not know whether the server 1100 contains the data itemsthat the authoritative client 1102 intends to publish, and where thosedata items do exist in the server 1100, the client 1101 does not knowtheir current values. Typically a client will rely on a server toprovide the items and their values, but in the case of an authoritativeclient 1102 it is the client 1102 which must provide the items and theirvalues. Thus, upon an initial connection, the authoritative client 1102must emit its entire data set and current values, ignoring andoverwriting any values already present in the server 1100. The currentinvention optionally provides this behavior, allowing any client toselect whether it will be authoritative for a particular data set.

Similarly, when an authoritative client 1102 disconnects from the cloudserver 1100, it must be able to inform other connected clients that theauthoritative source of data is no longer providing data. Theauthoritative client 1102 informs the server that it is authoritative,and additionally instructs the server 1100 to alter the properties ofthe data items in the server when the client disconnects to indicatethat those data items are “not connected”. The cloud server 1100 mustco-operate in this process, since the authoritative client has alreadydisconnected before the data items are marked as “not connected”, andthe server must propagate this change of status (sometimes referred toas “quality”) to other connected clients.

The combination of these important features ensures that the data on theserver 1100 is either consistent with the data on the authoritativeclient 1102, or it is in a known error state to indicate that theauthoritative client 1102 is not connected to the cloud server 1100.

Referring to FIG. 12, in another embodiment, a system is shown that issimilar to that shown in FIG. 11, but in a more visually descriptivemanner. In particular, exemplary types of servers may comprise embeddeddevices, SCADA systems or various connected consumer products, allproducing, propagating, sending and/or receiving data (some in realtime, some not). As illustrated in FIG. 12, these devices are behindfirewalls without open incoming firewall ports, thereby eliminatingdirect attacks from would-be hackers on the public network (not shown).On the same public network, a secure cloud server may receive outboundconnections initiated by the device behind the firewalls, as illustratedsymbolically by the large arrow across the firewall to the cloud server.Within the large arrow, data may be sent safely back to the devices.

Also shown in FIG. 12 is another aspect of the present invention,whereby the cloud server may employ methods described above to send datato RIAs for predictive maintenance or HMI displays, for data analysis(e.g. generating key performance indices), or to databases, or toprovide alerts (e.g. via email or SMS).

In another embodiment (not shown), a firewall is not provided in frontof the servers, clients or devices on the network, where theservers/clients/devices are configured to reject inbound connectionrequests. This is to be contrasted with employing firewalls that ignoreinbound connection requests to the server/client/device behind thefirewalls. In this embodiment, the operating system of theserver/client/device responds to inbound connection requests, after afashion, with a ‘nobody is listening’ response. While this configurationmay be less secure than employing firewalls, there are situations wherethe server/client/device is resource constrained to the point where itis not possible to include a firewall. Surprisingly, the presentinvention thus provides a method to provide a more secure method ofcommunication with resource-constrained devices.

It should be understood that when referring to a network residingbetween, for instance, a server and a client, the network itself maycomprise a series of network connections; that is, there is noimplication of a direct connection. Similarly, any server, client ordevice ‘on’ the Internet is understood to mean that the server, clientor device is connected to a network connection that is accessible to theInternet.

It is also understood that an authority on a data set, or anauthoritative holder of a data set, refers to the originator of the dataset, and all other recipients of the data set hold non-authoritativecopies. In the present invention, a server, client or device can inheritauthority from another server, client or device; for example, the cloudserver may act as an authority on a data set for another client/end-userdevice; the client/end-user device sees the cloud server as theauthority on the data set, but unknown to the client/end-user device,the cloud server may be propagating the data from a “true” authoritativeclient/end-user device connected to the cloud server. It is appreciatedthat the present invention allows for a myriad of combinations ofservers, clients, and devices interconnected and inheriting authorityover multiple data sets shared among them.

1.-20. (canceled)
 21. A method of receiving a data set, the methodcomprising: establishing a first network connection between a server anda first client; and receiving at the first client a first data set fromthe server over the first network connection, wherein (i) data in thefirst data set is provided from data in a second data set received atthe server from a second client via a second network connection, (ii)the second network connection is established by the sending of aninbound connection request by the second client to the server, thesecond client being inaccessible via inbound connection requests, and(iii) the data in the first data set is represented according to a firstdata representation independent of a data representation correspondingto the second client.
 22. The method of claim 21, wherein the data inthe second data set is represented according to the data representationcorresponding to the second client.
 23. The method of claim 22, whereinthe server converts the second data set into the first data set.
 24. Themethod of claim 21, wherein the first data representation is independentof a data representation corresponding to the first client.
 25. Themethod of claim 21, wherein the first data representation is an abstractrepresentation independent of data representations corresponding toindividual clients of the server.
 26. The method of claim 21, whereinthe first client displays a visualization of the first data set to auser.
 27. The method of claim 26, wherein the first client displays thevisualization using a web browser operating on the first client.
 28. Themethod of claim 26, wherein the first client displays the visualizationsubstantially in real time relative to the sending of the second dataset by the second client.
 29. The method of claim 26, wherein, based onthe displayed visualization, the user of the first client performs anaction.
 30. The method of claim 29, wherein the user of the first clientperforms the action when the displayed visualization satisfies acondition.
 31. The method of claim 30, wherein the displayedvisualization includes an indication of a value, and the condition issatisfied when the indication of the value reaches a threshold.
 32. Themethod of claim 29, wherein during the displaying of the visualization,the first client and the second client are in physical vicinity of eachother.
 33. The method of claim 26, wherein the second data set includesdata streaming from a data source, and wherein the first data setincludes a stream of data corresponding to the streamed data from thedata source.
 34. The method of claim 33, wherein the first clientcontinuously updates the visualization based on the data stream in thefirst data set.
 35. The method of claim 34, wherein the first clientcontinuously updates the visualization substantially in real timerelative to the streaming of data from the data source.
 36. The methodof claim 35, wherein the user of the first client performs an actionwhen the displayed visualization satisfies a condition.
 37. The methodof claim 36, wherein the displayed visualization includes an indicationof a value, and the condition is satisfied when the indication of thevalue reaches a threshold.
 38. A system of providing a data set,comprising: a processor configured to: establish a first networkconnection with a first client; and transmit a first data set to thefirst client over the first network connection, wherein (i) data in thefirst data set is provided to the processor from data in a second dataset received by the processor from a second client via a second networkconnection, (ii) the second network connection is established by thesending of an inbound connection request by the second client to theprocessor, the second client being inaccessible via inbound connectionrequests, and (iii) the data in the first data set is representedaccording to a first data representation independent of a datarepresentation corresponding to the second client.
 39. A non-transitorycomputer-readable medium having stored thereon one or more sequences ofinstructions for causing one or more processors to perform the methodaccording to claim 21.